scholarly journals Activity strategy and pattern of the Siberian jerboa (Orientallactaga sibirica) in the Alxa desert region, China

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10996
Author(s):  
Yu Ji ◽  
Shuai Yuan ◽  
Heping Fu ◽  
Suwen Yang ◽  
Fan Bu ◽  
...  

Rodents exhibit seasonal changes in their activity patterns as an essential survival strategy. We studied the activity patterns and strategies of the Siberian jerboa (Orientallactaga sibirica) in the Alxa desert region to better understand the habitats and behavioural ecology of xeric rodents. We conducted an experiment using three plots to monitor the duration, time, and frequency of the active period of the Siberian jerboa using infrared cameras in the Alxa field workstation, Inner Mongolia, China in 2017. The relationships between the activity time and frequency, biological factors (perceived predation risk, food resources, and species composition), and abiotic factors (temperature, air moisture, wind speed) were analysed using Redundancy Analysis (RDA). Our results showed that: (1) relative humidity mainly affected activities in the springtime; temperature, relative humidity and interspecific competition mainly affected activities in the summertime; relative humidity and perceived predation risk mainly influenced activities in the autumn. (2) The activity pattern of the Siberian jerboa altered depending on the season. The activity of the Siberian jerboa was found to be bimodal in spring and summer, and was trimodal in autumn. The activity time and frequency in autumn were significantly lower than the spring. (3) Animals possess the ability to integrate disparate sources of information about danger to optimize energy gain. The jerboa adapted different responses to predation risks and competition in different seasons according to the demand for food resources.

Author(s):  
Katarzyna Kwiatkowska ◽  
Katarzyna Kosińska-Kaczyńska ◽  
Izabela Walasik ◽  
Agnieszka Osińska ◽  
Iwona Szymusik

Background: No specific physical activity guidelines are available for women in multiple pregnancy. Aim of the study was to assess the knowledge and experience of women regarding physical activity during their latest twin pregnancy. Methods: A cross-sectional study including women after a twin delivery was conducted in Poland. A questionnaire was distributed in 2018 via web pages and Facebook groups designed for pregnant women. Results: 652 women filled out the questionnaire completely. Only 25% of women performed any physical exercises during twin gestation. The frequency of preterm delivery was similar in physically active and non-active participants. 35% of the respondents claimed to have gained information on proper activity from obstetricians during antenatal counselling while 11% claimed to be unable to identify the reliable sources of information. 7% of women admitted to feel discriminated by social opinion on exercising during a twin pregnancy. Conclusions: The population of women with a twin gestation is not sufficiently physically active and is often discouraged from performing exercises during gestation. Therefore, it is crucial to inform obstetricians to recommend active lifestyle during a twin gestation and to provide reliable information on physical activity to pregnant women. Further research on this topic is necessary in order for obstetric providers to counsel women on appropriate exercise with a twin pregnancy.


1998 ◽  
Vol 76 (10) ◽  
pp. 1878-1884 ◽  
Author(s):  
Edward P Levri

Foraging behavior can be influenced by such factors as predation risk, individual size, and parasite infection. Snails (Potamopyrgus antipodarum) placed in tanks with large rocks were exposed to four types of water: (1) water with crushed snails, (2) water from a tank in which fish (Gobiomorphus cotidianus) were fed only trout chow, (3) water from a tank where the fish were also fed snails, and (4) plain water. Snails could respond by moving to the top of rocks (where algal food was present) or to the bottom of rocks (where the predation risk was lower). The snails responded to fish chemicals by moving to the bottom of rocks. The response was dependent on snail size and fish diet. Smaller snails moved to the bottom of rocks more than larger snails did. Trematode-infected snails were found on top of the rocks more than other classes of snails, but infected snails still moved to the bottom of rocks in response to the fish predator. Snails eaten by fish in the field tend to be smaller than snails in the overall available population. Thus, snails that are more vulnerable to predation respond more intensely to the odor of fish by moving to the bottom of rocks. This size-dependent response to fish appears to be independent of the occurrence of trematode infection.


2016 ◽  
Vol 187 (5) ◽  
pp. 607-619 ◽  
Author(s):  
Ari E. Martínez ◽  
Juan P. Gomez ◽  
José Miguel Ponciano ◽  
Scott K. Robinson

2014 ◽  
Vol 6 (2) ◽  
pp. 371-376 ◽  
Author(s):  
Hijam S. Devi ◽  
D. R. Sharma

Seasonal abundance of citrus psylla (Diaphorina citri) Kuwayama was studied on Kinnow mandarin under Punjab conditions during 2012 and 2013. Population of D. citri was present throughout the year but only adults found surviving during December and February. There was no nymphal population when maximum temperature was > 39°C or < 7°C. Two population peaks of nymphs wer e observed, first in April-May and second in August- September. Thereafter, there was abrupt decline in nymphal population during June and July during both the years when the weather conditions i.e. maximum, minimum temperature (°C), relative humidity (%), rainfall (m m) and sunshine (hrs) ranged from 24.4-44, 22.4-31.8, 25.5-100, 0-108.0 and 0-13.5, respectively. Highest peaks of adult were found during May followed by June. With the decrease in temperature from the end of September, the population of D. citri started to decrease and reached its lowest during winter season. Correlation analysis for both the years indicated that maximum and minimum temperature, sunshine and rainfall were positively correlated with nymphal, adult and mixed population but the effect of rainfall on adult population was non-significant, while relative humidity was negatively correlated. The study is useful to find out the weak links of psyllid populations in relation to abiotic factors and that could be exploited to curb its infestation and disease transmission.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Douglas P. Chivers ◽  
Mark I. McCormick ◽  
Eric P. Fakan ◽  
Randall P. Barry ◽  
Maud C. O. Ferrari

AbstractLiving in mix-species aggregations provides animals with substantive anti-predator, foraging and locomotory advantages while simultaneously exposing them to costs, including increased competition and pathogen exposure. Given each species possess unique morphology, competitive ability, parasite vulnerability and predator defences, we can surmise that each species in mixed groups will experience a unique set of trade-offs. In addition to this unique balance, each species must also contend with anthropogenic changes, a relatively new, and rapidly increasing phenomenon, that adds further complexity to any system. This complex balance of biotic and abiotic factors is on full display in the exceptionally diverse, yet anthropogenically degraded, Great Barrier Reef of Australia. One such example within this intricate ecosystem is the inability of some damselfish to utilize their own chemical alarm cues within degraded habitats, leaving them exposed to increased predation risk. These cues, which are released when the skin is damaged, warn nearby individuals of increased predation risk and act as a crucial associative learning tool. Normally, a single exposure of alarm cues paired with an unknown predator odour facilitates learning of that new odour as dangerous. Here, we show that Ambon damselfish, Pomacentrus amboinensis, a species with impaired alarm responses in degraded habitats, failed to learn a novel predator odour as risky when associated with chemical alarm cues. However, in the same degraded habitats, the same species learned to recognize a novel predator as risky when the predator odour was paired with alarm cues of the closely related, and co-occurring, whitetail damselfish, Pomacentrus chrysurus. The importance of this learning opportunity was underscored in a survival experiment which demonstrated that fish in degraded habitats trained with heterospecific alarm cues, had higher survival than those we tried to train with conspecific alarm cues. From these data, we conclude that redundancy in learning mechanisms among prey guild members may lead to increased stability in rapidly changing environments.


2014 ◽  
Vol 51 (4) ◽  
pp. 769-776 ◽  
Author(s):  
K. A. Berger ◽  
H. S. Ginsberg ◽  
L. Gonzalez ◽  
T. N. Mather

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